In his response to Lawrence Harmon’s Aug. 24 op-ed column, Daniel Kane writes, “The fact is that Oregon-based Stand for Children is an outside group, even if it does have a Massachusetts chapter, and should not be influencing a local election” (“Outside influence on mayor’s race is what’s at issue,” Letters, Aug. 30). By that standard, the Boston Teachers Union should be excluded from contributing to mayoral candidates. As noted on the its website, the union is a local affiliate of the AFL-CIO and American Federation of Teachers.